The mitral and tricuspid valves inside the human heart include an orifice (annulus), two (for the mitral) or three (for the tricuspid) leaflets and a subvalvular apparatus. The subvalvular apparatus includes multiple chordae tendineae, which connect the mobile valve leaflets to muscular structures (papillary muscles) inside the ventricles. Rupture or elongation of the chordae tendineae results in partial or generalized leaflet prolapse, which causes mitral (or tricuspid) valve regurgitation. A commonly used technique to surgically correct mitral valve regurgitation is the implantation of artificial chordae (usually 4-0 or 5-0 Gore-Tex sutures) between the prolapsing segment of the valve and the papillary muscle.
This procedure was traditionally an open heart operation generally carried out through a median sternotomy and requiring cardiopulmonary bypass with aortic cross-clamp and cardioplegic arrest of the heart. Using such open heart techniques, the large opening provided by a median sternotomy or right thoracotomy enables the surgeon to see the mitral valve directly through the left atriotomy, and to position his or her hands within the thoracic cavity in close proximity to the exterior of the heart for manipulation of surgical instruments, removal of excised tissue, and/or introduction of an artificial chordae through the atriotomy for attachment within the heart. However, these invasive open heart procedures produce a high degree of trauma, a significant risk of complications, an extended hospital stay, and a painful recovery period for the patient. Moreover, while heart valve surgery produces beneficial results for many patients, numerous others who might benefit from such surgery are unable or unwilling to undergo the trauma and risks of such techniques.
Techniques for minimally invasive thoracoscopic repair of heart valves while the heart is still beating have also been developed. U.S. Pat. No. 8,465,500 to Speziali, which is incorporated by reference herein, discloses a thoracoscopic heart valve repair method and apparatus. Instead of requiring open heart surgery on a stopped heart, the thoracoscopic heart valve repair methods and apparatus taught by Speziali utilize fiber optic technology in conjunction with transesophageal echocardiography (TEE) as a visualization technique during a minimally invasive surgical procedure that can be utilized on a beating heart. More recent versions of these techniques are disclosed in U.S. Pat. Nos. 8,758,393 and 9,192,374 to Zentgraf, which disclose an integrated device that can enter the heart chamber, navigate to the leaflet, capture the leaflet, confirm proper capture, and deliver a suture as part of a mitral valve regurgitation (MR) repair. These minimally invasive repairs are generally performed through a small, between the ribs access point, followed by a puncture into the ventricle through the apex of the heart. Although far less invasive and risky for the patient than an open heart procedure, these procedures are still involving significant recovery time and pain.
It would be advantageous for a minimally invasive suture delivery system to be able to suture valve leaflets in a beating heart procedure without requiring an open surgical approach or an incision into the exterior ventricular wall in order to minimize blood loss and reduce recovery time and pain. To that end, various approaches to heart valve repair using intravascular access have been proposed, including U.S. Patent Publication Nos. 2007/0118151 and 2013/0035757 and U.S. Pat. Nos. 7,635,386 and 8,545,551.